ParseResult

A ParseResult is a data structure commonly used in programming and parsing systems to encapsulate the outcome of parsing operations, particularly in parsing expressions, grammars, or input data. It typically contains both the parsed value or result and metadata about the parsing process, such as the location or position where the parsing occurred.

In many parsing libraries and frameworks, such as those used in natural language processing, compilers, or configuration file parsers, a ParseResult serves as a standardized way to represent successful or failed parsing attempts. When parsing succeeds, the result often includes the extracted data along with information like the start and end positions of the parsed segment in the original input. If parsing fails, the result may indicate an error, such as a syntax violation or an unexpected token, along with details about where the failure occurred.

For example, in parser combinators—a functional programming technique for parsing—ParseResult is frequently used to represent either a successful parse with a value or a failure with an error message. This allows for chaining and composition of parsing operations while maintaining clarity about the outcome. The structure helps developers handle parsing errors gracefully and debug issues more effectively by providing context about the parsing state.

ParseResult is particularly useful in scenarios where parsing is a critical part of the workflow, such as in compilers where syntax must be validated before code generation, or in configuration systems where malformed input must be detected early. By encapsulating both success and failure cases, it promotes robust and maintainable parsing logic.